3-(Aminocarbonyl)-7-oxabicyclo(2.2.1)hept-5-ene-2-carboxylic acid, monoammonium salt 60671-62-7 7-Oxabicyclo(2.2.1)hept-5-ene-3-carbamoyl-2-carboxylate, ammonium salt KF 392 KF-392